BR112019009598A2 - process for reducing the volatile organic compound content of granulated plastomers, process for producing granulated plastomer and granulated plastomer - Google Patents

Abstract

The present invention relates to a process for reducing the volatile organic compound content of granulated plastomers having a density of 883 kg / m3 or less and a mfr2 of 100.0 g / 10 minutes or less (iso 1133 with a charge of 2 , 16 kg and 190 ° c) below 65 ppm (voc, vda277), wherein the process comprises the steps of providing a raw granulated plastomer in a treatment vessel, the raw granulated plastomer having a density equal to or greater than less than 883 kg / m3 and mfr2 equal to or less than 100,0 g / 10 minutes (iso 1133 with a loading of 2,16 kg and 190 ° c) and a volatile organic compound content (voc, vda277) exceeding 150 ppm, subjecting said raw granulated plastomer to a gas stream in the range 30 m3 / (h¿t) to 150 m3 / (h¿t) for an aeration time of less than 96 hours, the gas having a minimum temperature of at least 26 ° C, measured at a treatment vessel gas inlet, and a maximum temperature of 4 ° C below vicat eratura (10 n, iso 306) of the raw granulated plastomer, or 35 ° C measured at the gas inlet of the treatment vessel, whichever is less; and recover the granulated plastomer.

Description

PROCESS TO REDUCE THE CONTENT OF VOLATILE ORGANIC COMPOUNDS OF GRANULATED PLASTOMERS, PROCESS FOR PRODUCTION OF GRANULATED PLASTOMER AND GRANULATED PLASTOMER

Technical field of the invention [001] The present invention relates to a process for obtaining plastomers with low content of volatile organic compounds (VOC) and to a process for reducing the content of volatile organic compounds in granulated plastomers to below 65 ppm (VOC, VDA277).

Background of the invention [002] There are several known options for removing volatile materials that involve the use of solvents such as water, the use of steam as well as hot gas streams.

[003] A process for separating volatile material from particulate is known which comprises (a) introducing the polymer in particulate form into a purge vessel, optionally causing it to move through the vessel in a substantially impiston flow mode ( plugflow), (b) heat the polymer in particulate form in the purge vessel to a temperature above 30 ° C, preferably 50 ° C, more preferably at least 70 ° C, but not so high to avoid agglomerations, that is, not more than approximately 5 ° C below Vicat softening temperature. This process also comprises the steps of and / or maintaining the polymer at a temperature in that range in the purge vessel, (c) introducing air into the purge vessel in a counter-current to the movement of the polymer in particulate form

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2/37 to remove the volatile material from it, (d) remove the particulate polymer from the WO 02/088194 purge vessel.

[004] WO 2006/067146 also summarizes the prior art using hot gas stream to remove volatile materials, in which the required aeration time is inversely proportional to the gas temperature, meaning that a compromise must be reached to prevent the pellets melt and stick to each other. According to WO 2006/067146, the typical values of temperature and residence time for polyethylene are 80 to 110 ° C, 5 to 50 hours and 500 to 5000 m ³ / h / t of hot gas in the product. In the process of WO 2006/067146, the treatment with hot air in the silo is combined with a pretreatment by water bath and cooling after treatment.

[005] A similar process is described in WO 2004/039848: the polymer in particulate form is heated to a temperature above 30 ° C, however, not too high to avoid agglomeration, in which substantially all the heating of the particles occurred in the Treatment vessel is achieved by preheating the gas charge, usually air, and introducing the gas charge into the treatment vessel. WO 2004/039848 also describes that, for lower density polyolefins such as copolymers of ethylene and higher polyolefin with a density between 915 and 945 kg / m ³ , the temperature should be in the range between 60 and 80 ° C. Again, as a general recommendation, the temperature to which the polymeric material is heated should not be above approximately 5 ° C below the softening temperature

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Vicat. WO 2004/039848 also teaches the introduction of gas in the bottom of the treatment container at a flow rate between 2 and 10 liters / h and per centimeter frame of the transverse area of the treatment container.

[006] However, the known methods for reducing volatile material still fail for specific purposes. For example, in the production of low density polyolefins and low flow rate, especially low density C2C6 or C2C8 plastomers, by solution polymerization, the amounts of volatiles are high, as above 400 ppm, according to measurement VDA277 in granulated polymer. This is usually a problem for low density plastomers, since in order to achieve lower densities, larger quantities of larger comonomers, such as hexene or octene, must be fed into the process. Consequently, since larger comonomers (ie, hexene, octene) are more difficult to remove than smaller comonomers (ie, butene), high amounts of volatiles pose a particular problem to be solved for low density plastomers. The amount of volatiles becomes even more problematic, since plastomers are produced by a solution polymerization process, resulting in laborious workup (separation and isolation). It should be noted that such high amounts of volatiles are obtained despite some reduction occurring naturally during the extrusion step. The high volatile content is especially problematic for low density plastomers, as these have melting temperatures

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4/37 as low as 47 ° C according to ISO 11357, the Vicat temperature being only 38 ° C.

[007] Needless to say, several low density plastomer applications require extremely low levels of volatiles such as below 65 ppm (VOC, VDA277), preferably below 50 ppm and, in certain cases, even below 10 ppm .

Summary of the invention [008] The present invention is based on the discovery that the volatile content of granulated plastomers with densities equal to or less than 883 kg / m ³ and with MFR2 equal to or less than 100 g / 10 minutes (ISO 1133 with load 2.16 kg and 190 ° C) that initially contained volatile organic compounds (VOC, VDA277) content above 150 ppm, can be significantly reduced in less than 96 hours using a gas stream with temperature between 26 ° C and 4 ° C below the Vicat temperature (10 N, ISO 306) of the granulated plastomer; in any case, with the temperature not exceeding 35 ° C.

[009] The present invention provides in this sense:

a process to reduce the content of volatile organic compounds in granulated plastomers having:

- density equal to or less than 883 kg / m ^3, and

- MFR2 equal to or less than 100.0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C);

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5/37 for below 65 ppm (VOC, VDA277), where the process comprises the steps of:

a) supply a raw granulated plastomer in a treatment container, the raw granulated plastomer having:

- density equal to or less than 883 kg / m ³ ; and

- MFR2 equal to or less than 100.0 g / 10 minutes (ISO

1133 with a load of 2.16 kg and 190 ° C); and

- content of volatile organic compounds (VOC, VDA277) above 150 ppm,

b) subjecting said granulated plastomer in a raw state to a gas flow in the range between 30 m ³ / (ht) and 150 m ³ / (ht) for an aeration time of less than 96 hours, the gas having:

- a minimum temperature of at least 26 ° C measured at the gas inlet of the treatment vessel, and

- a maximum temperature of 4 ° C below the Vicat temperature (10 N, ISO 306) of the raw granulated plastomer or 35 ° C measured at the gas inlet of the treatment vessel, whichever is the lower; and

c) recovering the granulated plastomer;

[0010] The present invention further provides:

a process for the production of granulated plastomer having:

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- content of volatile organic compounds (VOC, VDA277) below 65 ppm,

- density equal to or less than 883 kg / m ³ ; and

- MFR2 equal to or less than 100.0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C);

where the process comprises the steps of:

a) polymerize ethylene and 1-octene by solution polymerization in at least one polymerization reactor to produce a crude polymerization mixture,

b) recovering said crude polymerization mixture from at least one polymerization reactor and feeding said crude polymerization mixture to at least one flash vessel, through which at least partially removing the solvent, unreacted monomer and unreacted comonomer to produce a raw plastomer,

c) subjecting the raw plastomer to the mixture, preferably by an extruder or static mixer, and granulation,

d) recover the granulated plastomer in the raw state having:

- density equal to or less than 883 kg / m ³ ; and

- MFR2 equal to or less than 100.0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C); and

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7/37 content of volatile organic compounds (VOC, VDA277) above

150 ppm,

e) subjecting said granulated plastomer in a raw state, in a treatment container, to a gas flow in the range between 30 m ³ / (ht) and 150 m ³ / (ht) for an aeration time of less than 96 hours, having gas:

- a minimum temperature of at least 26 ° C, measured at a gas inlet of the treatment vessel, and

- a maximum temperature of 4 ° C below the Vicat temperature (10 N, ISSO 306) of the granulated plastomer or 35 ° C measured at the gas inlet of the treatment vessel, whichever is lower; and

f) recover the granulated plastomer.

Definitions [0011] The content of volatile organic compounds (VOC, VDA277) is a measure of the emissions of plastic materials such as low density plastomers, which are caused by low molecular weight components in the polymeric material. These low molecular weight components can be residual monomers, oligomers, additives, plasticizers and / or degradation products.

[0012] The term gas flow, in this specification, indicates the volume of gas flowing per hour using a ton of plastomer as a reference.

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8/37 [0013] On the other hand, in this specification, the term gaseous current, indicates the volume of gas flowing per hour taking as reference the cross-sectional area of the treatment vessel, measured, p. at the gas inlet of the treatment vessel.

[0014] The term gas in this specification indicates any gas suitable for heating to at least 50 ° C and suitable for removing volatile organic compounds from plastomers. Suitable gases are, for example, nitrogen or air or mixtures of these. Simply for reasons of cost, the most preferred gas for the process of the invention is air.

[0015] The gas that leaves the bed of the pellets, that is, the one that loaded the volatile organic compounds is indicated as the exhaust gas in this application.

[0016] The term granular, in this specification, indicates a plastomer in the form of pellets and / or granular material. Normally, pellets or granulated material will result from pelletizing or granulating. For example, pellets can be formed by forcing the molten plastomer through a mold and subsequently obtaining pellets with an underwater granulator.

[0017] Plastomers, in this specification, constitute copolymers of ethylene and alpha-olefins, which combine properties of elastomers and plastics, that is, they may have properties similar to rubber and the processability of plastics.

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9/37 [0018] The term aeration or aeration process, in this specification, indicates a process or process step, in which a compound is subjected to a gas flow.

[0019] The term aeration pressure, in this specification, refers to the pressure that is present inside the treatment container. When a silo is used as the most conventional treatment container, pressure must be easily measured in the free headspace (empty space at the top), especially at the free edge or in the gas outlet duct at the top of the silo.

[0020] A batch aeration process is a process in which plastomers to be aerated are introduced into treatment containers, in which the entire batch is subjected to one stage of the aeration process at a time, and the aerated plastomer is removed from the treatment container all at once after finishing the process. Unlike a continuous process, a batch process cannot be performed for an arbitrary period of time, since the state of the material (eg, the volatile content) in the treatment container defines the time until when the process must be stopped, p. eg to remove the aerated plastomer and refill with plastomer to be aerated.

[0021] The term preheating step indicates a step that generally precedes the treatment step, in which the shaped plastomers are heated to the desired temperature for treatment. Preheating granulated plastomers can facilitate the treatment process and reduce the time required for the overall process. In addition, certain means

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10/37 preheating can reduce the energy consumption of the treatment process.

[0022] Aeration time is the period of time between the beginning and the end of a gas stream and the resulting gas flow in the treatment vessel. Thus, as soon as the gas stream is started and adjusted and the gas flow continues through the treatment vessel, the aeration time is running. Respectively, as soon as the gas stream is stopped, that is, when the desired desired VOC content is reached, the aeration time ends. If granulated plastomers are preheated by external means, e.g. ex. , without a gas flow, the aeration time also starts with the beginning of the gas stream after the preheating step. If the granulated plastomers are preheated with the help of a gas flow, the aeration time already starts with the gas flow of the preheating step and ends with the gas flow stop after the actual treatment step, ie , when the desired desired VOC content is reached.

Detailed description of the invention [0023] It was surprisingly found that the VOC reduction rates obtained by the processes of the invention are excellent due to the given energy effort and aeration time. Furthermore, the processes of the invention can be used on a commercial scale to homogeneously reduce volatile VOCs to acceptable levels with relatively low effort. In addition, there is no need for additional circulation of the granulated plastomer.

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11/37 [0024] In the process according to the present invention, ο raw granulated plastomer has an average particle size between 2.5 and 4.5 mm, measured according to the method described herein.

[0025] In a process according to the present invention, the raw granulated plastomer is supplied in a treatment container. In the simplest form, this can be any container or tube that allows sedimentation of the plastomer and injection of gas.

The raw granulated plastomer has MFR2 equal to or less than 100 g / 10 minutes, preferably equal to or less than 20 g / 10 minutes and even more preferably equal to or less than 6 g / 10 minutes.

[0027] Furthermore, granulated plastomers have a density of 883 kg / m ³ or less, more preferably 870 kg / m ³ or less.

[0028] In the process according to the present invention, the raw granulated plastomer is subjected to a gas stream in the range between 20.0 liters / (h-cm ² ) and 35.0 liters / (h-cm ² ) , preferably to a gas stream in the range between 22.0 liters / (h · cm ² ) and 35.0 1itros / (h · cm ² ), most preferably, to a gas stream in the range between 25.0 liters / (h-cm ² ) and 35.0 liters / (h-cm ² ).

[0029] In the process according to the present invention, the aeration pressure is preferably between 500 hPa and 1300 hPa, more preferably between 700 hPa and 10 60 hPa, even more preferably between 800 hPa and 10 60 hPa, the most being

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12/37 ambient pressure preferable. Specifically, the process of the present invention does not involve the use of a device to lower the pressure in the treatment vessel, such as a pump. Thus, the pressure in the container is preferably left at ambient pressure. The pressure in the treatment vessel is therefore dependent on the height of the silo, the temperature and the speed of the gas flow in the treatment vessel. In a preferred embodiment, the pressure at the inlet of the gas stream is 0.1 to 0.3 bar higher than the pressure outside the treatment vessel. More preferably, the pressure at the inlet of the gas stream is 0.2 bar higher than the pressure outside the treatment vessel.

[0030] In a first preferred embodiment of the present invention, the content of volatile organic compounds in granulated plastomers is reduced in the process to 20 ppm or less, preferably to 15 ppm or less, most preferably to 10 ppm or less. This modality aims at a plastomer with the lowest amount of volatile organic compounds possible.

[0031] The aeration time of the first preferred mode depends on the material to be broken and the desired VOC content, as well as the treatment conditions (aeration). In the process of inventing the first embodiment, the aeration time is less than 96 hours. Normally, an aeration time of less than 80 hours or less than 72 hours will be sufficient.

[0032] The first preferred embodiment of the invention relates to a process for reducing the content of volatile organic compounds in granulated plastomers having:

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- density equal to or less than 883 kg / m ^3, and

- MFR2 equal to or less than 100.0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C);

below 20 ppm (VOC, VDA277), where the process comprises the steps of:

a) supply a raw granulated plastomer in a treatment container, the raw granulated plastomer having:

- density equal to or less than 883 kg / m ³ ; and

- MFR2 equal to or less than 100.0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C); and

- content of volatile organic compounds (VOC, VDA277) above 150 ppm,

b) subjecting said granulated plastomer in a raw state to a gas flow in the range between 30 m ³ / (ht) and 150 m ³ / (ht) for an aeration time of less than 96 hours, the gas having:

- a minimum temperature of at least 26 ° C, measured at a gas inlet of the treatment vessel, and

- a maximum temperature of 4 ° C below the Vicat temperature (10 N, ISO 306) of the raw granulated plastomer or 35 ° C measured at the gas inlet of the treatment vessel, whichever is the lower; and

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c) recover the granulated plastomer.

[0033] In a second preferred embodiment of the invention, the content of volatile organic compounds in granulated plastomers is reduced in the process to 65 ppm or less, preferably 60 ppm or less, the most preferred being 55 ppm or less. This modality aims at a plastomer with a reasonable amount of volatile organic compounds, achieved in a short favorable period of aeration time. This modality aims, while aiming at a balance between reduction of volatile organic compounds and global costs of the process.

[0034] The aeration time of the second preferred mode is less than 44 hours. Normally, an aeration time of less than 30 hours or less than 25 hours will be sufficient.

[0035] The second preferred embodiment of the invention relates to a process for reducing the content of volatile organic compounds in granulated plastomers having:

- density equal to or less than 883 kg / m ^3, and

mfr ₂ equal or less than 100.0 g / 10 minutes (ISO 1133 with load 2.16 kg and 190 ° C);

below 65 comprises the steps ppm (VOC, of: VDA277), in that the process a) provide a plastomer granulated in gross state in

a treatment container, the granulated plastomer being raw:

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- density equal to or less than 883 kg / m ³ ; and

mfr ₂ equal or less than 100.0 g / 10 minutes (ISO 1133 with load 2.16 kg and 190 ° C); and

- content of volatile organic compounds (VOC

VDA277) above 150 ppm,

b) subjecting said granulated plastomer in a raw state to a gas flow in the range between 30 m ³ / (ht) and 150 m ³ / (ht) for an aeration time of less than 44 hours, with the gas:

an temperature minimum at least 26 ° C, measured in an entry of gas of the container of treatment, and an temperature maximum 4 ° C below of temperature

Vicat (10 N, ISO 306) of the raw or 35 ° C granulated plastomer measured at the gas inlet of the treatment vessel, whichever is the lower; and

c) recover the granulated plastomer.

[0036] The following bands can be applied to all modalities according to the invention.

[0037] The gas stream according to the present invention has a minimum temperature of at least 26 ° C. In addition, the gas stream according to the present invention has a maximum temperature of 4 ° C below the Vicat temperature (10 N, ISO 306) of the granulated plastomer or 35 ° C, the value that

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16/37 is lower. Thus, if the Vicat temperature (10 N, ISO 306) of the granulated plastomer is 38 ° C, the temperature of the gas stream must not exceed 34 ° C. However, if the Vicat temperature (10 N, ISO 306) of the granulated plastomer is 40 ° C or even 45 ° C, the maximum temperature of the gas stream is 35 ° C. Preferably, the maximum temperature of the gas stream is 32 ° C, more preferably 31 ° C. The minimum temperature of the gas stream is preferably 27 ° C and more preferably 28 ° C, most preferably 29 ° C.

[0038] As the specific thermal capacity of the plastomer together with the mass of the plastomer is significant when compared to the specific thermal capacity of the gas together with the mass of the gas, it is necessary to be aware that the temperatures of the gaseous stream for the entry and exit aeration are fulfilled. Thus, if the plastomer is supplied at a relatively low temperature in a silo, preheating is necessary. Preheating can of course also be carried out by the gas stream and the temperatures specified above. However, during such preheating, the temperature at the outlet will be lower, as the heat is transferred to the plastomer.

[0039] To shorten the preheating phase, avoid loss of energy during aeration and / or also increase homogeneity in the cross section, the use of an insulated treatment container, preferably an isolated silo is preferred.

[0040] For the same reasons, it is also preferable to use a raw granulated plastomer at a temperature

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17/37 between 26 ° C and 34 ° C, more preferably between 27 ° C and 32 ° C with the most preferable between 29 ° C and 31 ° C.

[0041] Thus, the raw granulated plastomer is preferably preheated before the aeration time is started to accelerate the process. In general, any heating measures known in the prior art can be used for preheating. Either the granulated plastomer or the treatment container, that is, the silo, or both together can be preheated.

[0042] The plastomer, the treatment container or both together can be preheated externally. By the term preheated externally, it is understood that preheating is carried out by external means of preheating. The external means of preheating can be solar collectors, heating by electricity or heating by any type of radiation. The external preheating of the treatment container occurs by heating the walls of the container. External heating of the container walls can occur by general means for heating a container, e.g. eg by electricity or also simply by sunlight falling directly on the outer wall of the container. The treatment vessel and plastomer can also be preheated separately by external means of preheating and, after preheating, the preheated plastomer is supplied in the preheated treatment vessel.

[0043] It could also be considered preheating not to let the pellets cool, which are produced,

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18/37 extruded and transformed into pellets just before. Such produced pellets normally have a temperature close to or above 25 ° C. Consequently, the plastomer production process and the process of the present invention can be carried out in an integrated process.

[0044] Preheating can also be carried out by starting the process with a higher gas flow and reducing the gas flow to the desired gas flow when the temperature at the top of the silo is close to the temperature at the bottom of the silo. Preheating, e.g. ex. , with steam in a passage heater is not an option due to the low Vicat temperatures of the plastomer. Thus, the preheat must also meet the conditions for the gas flow temperature, as defined for the gas flow above.

[0045] Preferably, the plastomer, the treatment container or both together are preheated externally.

[0046] In the process according to the present invention, the gas flow is preferably in the range between 30 m ³ / (ht) and 150 m ³ / (ht), more preferably in the range between 40 m ³ / (ht) and 130 m ³ / (ht). For the purposes of cost advantages, the lowest gas flow in the range between 40 m ³ / (ht) and 60 m ³ / (ht) is preferred.

[0047] In accordance with the present invention, gas is injected from the bottom of the treatment vessel. Preferably, the gas is injected through a gas distribution ring,

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19/37 located in the bottom cone of a silo, resulting in a gas flow from the bottom to the top through the pellet bed. In a further embodiment of the invention, there is more than one distribution ring provided in the treatment container, e.g. eg, located sequentially along the path of the gas flow in the pellet bed and / or with different radii ensuring that the gas distribution in the pellet bed is homogeneous. Preferably, the gas is introduced through nozzles in the distribution ring. More preferably, the gas is introduced through at least two nozzles per distribution ring.

[0048] Alternatively, in another mode, if the process is carried out continuously, the gas is preferably also injected into the bottom of the treatment container, but, it flows up and down, in the opposite direction to the flow of the moving pellets.

[0049] In an especially preferred embodiment, the gas stream is in the range between 25.0 liters / (h-cm ² ) and 35.0 1 i tr / / (h · cm ² ), the aeration pressure is 800 hPa at 1060 hPa and the maximum temperature of the gas stream, 31 ° C with a minimum temperature of the gas stream of 27 ° C. This modality is preferably combined with gas injection from the bottom.

[0050] In a particularly preferred second embodiment, the gas stream is in the range between 25.0 liters / (h-cm ² ) and 35.0 1 i / / / (h · cm ² ), the aeration pressure is from 800 hPa to 1060 hPa, the maximum temperature of the gas stream is 31 ° C with a minimum temperature of the gas stream of 27 ° C, with

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20/37 the gas flow preferably in the range between 40 m ³ / (ht) and 60 m ³ / (ht). This modality is preferably combined with gas injection from the bottom.

[0051] The treatment container is preferably a silo. It is highly preferable to use an insulated silo. It should be understood that the use of an isolated silo is preferred for all of the modalities described herein.

[0052] In a further embodiment of the invention, the bed height / diameter ratio formed by the plastomer pellets used for the process of the present invention is at least 1, more preferably 3. In addition, the bed height / diameter ratio formed by the pellets of the plastomers used for the process of the present invention does not exceed 6, more preferably does not exceed 5.

[0053] The process according to the present invention is preferably carried out in batches. Continuous aeration is undesirable, as homogeneity could not be guaranteed. This results from the fact that, for the desired residence times in the process, the treatment containers for a continuous process would be very large. In addition to practical considerations, such large treatment containers behave in an undesirable manner in terms of homogeneity of the pellets due to the behavior of the pellet flow.

[0054] In the process according to the present invention, the granulated plastomer is preferably not mixed or moved during the entire treatment by mechanical means. THE

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21/37 the absence of mechanical mixing and similar measures, such as refilling or the like, is especially advantageous, since the creation of fine particles is avoided. In addition, the degree of filling is greater without the need for mechanical stirring or transfer to another treatment container / silo.

[0055] The process according to the present invention is especially advantageous for raw granulated plastomer obtained by solution polymerization. This is due in particular to the fact that the raw granulated plastomer in its raw state, as obtained from the production process (ie, solution polymerization reactor, degassing unit (s) and extruder (s)) normally contains relatively high amounts of VOC. Consequently, the content of volatile organic compounds is generally too high for demanding end-use applications. In addition, the raw granulated plastomer, as obtained directly after cutting, should not be cooled to room temperature, but recovered in the treatment container, that is, preferably directly in the isolated silo. Thus, preheating of the plastomer is not necessary. The total process for producing the plastomer and aeration are considered an integrated process.

[0056] The process according to the present invention comprises a step of preferably subjecting the gas downstream of the treatment vessel to means for removing hydrocarbons. Preferably, these media are selected from one or more catalytic oxidation units, a

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22/37 or more carbon adsorption column (drums) and / or any conventional exhaust treatment known in the art. Even more preferably, these media are carbon adsorption columns (drums). Preferably, when it is air and / or nitrogen, the aeration gas can be emitted to the atmosphere after removal of the hydrocarbons.

[0057] In addition, the heat still contained in the discharged gas can be transferred to the gas used for aeration by means of heat exchangers known in the art, if the gas removed from the environment has a lower temperature than necessary for the process . In another embodiment of the invention, a cooler is used, if the gas removed from the environment has a higher temperature after compression than the temperature required for the process. Preferably, in such a chiller, the water is cooled to ± 10 to ± 15 ° C in a refrigerator and subsequently used in a heat exchanger to cool the gas from ± 40 ° C to ± 30 ° C.

[0058] In the process according to the present invention, the exhaust gas is preferably discharged into the atmosphere. Alternatively, but less preferably, the exhaust gas is used again after the VOCs are separated.

[0059] As mentioned above, the present invention relates to an integrated process for the production of granulated plastomer having:

- content of volatile organic compounds (VOC, VDA277) below 65 ppm,

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- density equal to or less than 883 kg / m ³ ; and

- MFR2 equal to or less than 100.0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C);

where the process comprises the steps of:

a) polymerize ethylene and 1-octene by polymerization in solution, in at least one polymerization reactor, to produce a crude polymerization mixture;

b) recovering said polymerization crude mixture from at least one polymerization reactor and feeding said polymerization crude mixture to at least one flash vessel, thus removing, at least partially, the solvent, unreacted monomer and unreacted comonomer to produce a raw plastomer;

c) subjecting the raw plastomer to the mixture, preferably by an extruder or static mixer, and granulation;

d) recover the granulated plastomer in the raw state having:

- density equal to or less than 883 kg / m ³ ; and

- MFR2 Equal or less than 100.0 g / 10 minutes (ISO 1133 with load of 2.16 kg and 190 ° C); and

- content of volatile organic compounds (VOC, VDA277) above ppm,

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e) subjecting said granulated plastomer in a raw state in a treatment vessel to a gas stream of 10.0 liters / (h.cm ² ) to 35.0 liters / (Irem ² ) for an aeration time of less than 96 hours , having gas:

- a minimum temperature of at least 26 ° C, measured at a gas inlet of the treatment vessel, and

- a maximum temperature of 4 ° C below the Vicat temperature (10 N, ISO 306) of the raw granulated plastomer or 35 ° C measured at the gas inlet of the treatment vessel, whichever is the lower;

f) recover the granulated plastomer.

[0060] All the preferred bands and modalities, as described above, also apply to this integrated process and are incorporated herein by reference to them.

[0061] It is especially preferred that there is no intermediate step in the treatment vessel between granulation and recovery of the raw plastomer. In particular, the raw granulated plastomer is sent directly to the treatment container, preferably to an isolated silo, thus avoiding any unnecessary heat loss. It was found that the aeration time of the process can be described by a mathematical model of the process. The effect of the absence of an intermediate step between granulation and recovery of raw plastomers can thus be understood by modeling certain series, provided in

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Table 1 below. The model used follows the formulas below:

[0062] desorption rate of

VOC is described, with the assumption that the majority of

VOCs is made up of components

C8, by:

where the empirical desorption parameter (kdes) is constant over the aeration time in the polyethylene to an average temperature during the said aeration time:

des i

des, the \ C (1- /)

F ^ act

RT [0063]

Crystallinity (χ) is calculated as follows:

[0064] on

P in Pam cry 'am

The temperature can be determined by:

d ( ^m Poi-Cp, poi- ^T ) _φ dt v, gas i gas that the thermal capacity of the plastomer depends on crystallinity:

P, pol

P, cry

P, am

Giving:

Τ (θ = 71- (71-Τ _ο ρ

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26/37 [0065] The average temperature during the aeration time t * is estimated by:

(7) where,

R is the gas constant,

Eact is the activation energy (determined experimentally) for the semiempirical diffusion constant, kdesc, o is the pre-exponential factor (given mind) for the semiempirical diffusion constant, χ is the crystallinity of the plastomer, p _P oi is the density of the plastomer, pgas is the density of the gas, p _C ry is the density of 100% crystalline polyethylene (1005 kg / m ³ ) p _a m is the density of 100% amorphous polyethylene (855 kg / m ³ ) rroipoi is the mass total plastomer in the silo, Ev _r gas is the volumetric flow of gas,

Tl is the temperature of the gas,

To is the temperature of the pellets at the start of the process,

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Cp, gas is the thermal capacity of the gas,

C _P , _P oi is the thermal capacity of the plastomer,

Cp, am is the thermal capacity of 100% amorphous polyethylene (2.87 kJ / kg-K),

Cp, cry is the thermal capacity of 100% crystalline polyethylene (1.96 kJ / kg-K),

VOCt = end is the final volatile content (modeled by Cs (t)),

VOCt = o is the initial volatile content (modeled by Cs, o) t is the aeration time in [h].

Table 1

Series 1 Series 2 Series 3 Series 4 Series 5 Series 6 Series 7 Φν, gas [m ³ / h] 3000 3000 3000 3000 3000 3000 3000 Popoi [kg / m ³ ] 867 867 880 880 880 880 875 Pgas (air) [kg / m ³ ] 1, 4 1, 4 1, 4 1, 4 1.4 1.4 1.4 mpoi [t] 70 70 70 70 50 50 70 Gas flow [m ³ / (h · t)] 42, 9 42, 9 42, 9 42, 9 60.0 60.0 42, 9 Tl [° C] 30 30 30 30 30 30 29 To [° C] 15 25 15 25 15 25 15 VOCt = o [ppm] 204 204 200 200 210 210 200 VOCt = end [ppm] 1, 8 1, 8 10 10 50 50 20 t [h] 78 64 58 46 29 22 45

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Series 1 Series 2 Series 3 Series 4 Series 5 Series 6 Series 7 Cp, pol [kJ / (kg-K)] 2.80 2.80 2.72 2.72 2.72 2.72 2.75 Cp, gas (air) [kJ / (kg-K)] 1.01 1.01 1.01 1.01 1.01 1.01 1.01

R = 8.3145 J / (mol * K); Eact = 31.0575 kJ / mol;

kd (0) = 5.591241 s' ¹ [0066] It can be seen from Table 1 that the series with high To 25 ° C need significantly less time to reach the desired VOCt = end level when compared to series with such an intermediate step indicated by the lowest To 15 ° C. In the case of series with high To 25 ° C, the plastomer is preferably transferred directly from the granulation process to the aeration treatment process according to the invention.

[0067] Furthermore, it can be seen from Table 1 that Series 5 and 6 represent the second modality, aiming at a balance between a reasonable reduction of volatile organic compounds and favorable process costs, as established above, while Series 1- 4 represent the first modality aimed at low amounts of volatile organic compounds.

[0068] In the processes of the present invention, that is, the aeration process and the integrated process as described above, the shorter aeration time is not specifically limited. Normally, aeration will be carried out until the content of volatile organic compounds in the granulated plastomer

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Raw 29/37 versus the final content of volatile organic compounds in the granulated plastomer is at least 4: 1, preferably at least 10: 1, most preferably at least 20: 1; that is, if the content of volatile organic compounds in the raw granulated plastomer (as the starting material) has a VOC content (VDA277) of 200 ppm, aeration is preferably carried out until the final content of volatile organic compounds in the granulated plastomer (ie, the final product) will be below 65 ppm.

[0069] The processes of the present invention, that is, the aeration process and the integrated process, as described above, are especially advantageous in and for the production of granulated plastomer with MFR2 equal to or less than 6.0 g / 10 minutes ( ISO 1133 with a load of 2.16 kg and 190 ° C). The softer plastomers benefit from the very smooth process conditions of the processes of the invention. The accumulation of fine particles and agglomerations is successfully prevented. The advantageous nature is even more pronounced for granulated plastomer with MFR2 equal to or less than 2.0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C) with granular plastomer with MFR2 equal to or less than 1 , 0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C).

[0070] In yet a further aspect, the processes of the invention are especially advantageous in the treatment and for the production of granulated plastomer with density equal to or less than 880 kg / m ³ , preferably with density less than 875 kg / m ³ , being more preferably less than 870 kg / m ³ .

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Furthermore, the processes of the invention preferably concern the production or treatment of granulated plastomer with a flexural modulus equal to or less than 20 MPa, preferably equal to or less than 15 MPa, more preferably an equal flexural modulus or less than 10 MPa. When producing or treating such extremely soft materials, the processes of the invention successfully prevent agglomerations and still allow for VOC reduction.

Experimental part

Testing methods

a) MFR [0072] The flow rate (MFR) was determined according to ISO 1133 at 190 ° C. The load under which the measurement is conducted is given as the subscript. Thus, the MFR under the 2.16 kg load is indicated as MFR2. The MFR21 flow rate is determined correspondingly to 190 ° C under a load of 21.6 kg.

b) Density [0073] Density was measured according to ISO 1183-1: 2004 Method A with a compression molded specimen, prepared according to EN ISO 1872-2 (February 2007) and is supplied in kg / m ³ .

c) Volatile VOC (VDA277) [0074] The total emission of plastomers was determined by heaspace extraction according to VDA 277: 1995 using gas chromatography and a headspace method. The equipment was an Agilent gas chromatograph with WCOT capillary column

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31/37 (wax-like) 30 m long and 0.25 mm x 1.0 micrometres internal diameter (film thickness: 1 pm). A flame ionization detector was used with hydrogen as a fuel gas. The GC settings were as follows: isothermal analysis 3 minutes at 50 ° C, heating to 200 ° C with 12 K / minute, isothermal analysis 4 minutes at 200 ° C, injection temperature: 200 ° C, detection temperature: 250 ° C, carrier gas: helium, separation, 1:20 constant flow mode and carrier gas flow rate of 1 mL / minute. The emission potential was measured based on the sum of all values provided by the substances emitted after analysis by gas chromatography and detection by flame ionization with acetone as the calibration standard. The introduction of samples (pellets, approximately 2 g) was by analysis of the headspace (20 mL flask in the headspace) after conditioning at 120 ° C for 5 hours before measurement. The unit is microgram of carbon per gram of sample, respectively ppm.

d)

The average particle size (plastomer pellets) [0075] The particle size distribution and shape evaluation were performed based on image analysis methods. A high-speed in-line layer obtained a two-dimensional image of each particle in free fall mode. The system measured the size of these particles as the diameter of an equivalent circle. The pellets were divided into nine classes: 1000 pm, 2000 pm, 2500 pm, 3000 pm, 3500 pm, 4000 pm, 5000 pm, 6000 pm,> 6000 pm.

[0076] For each particle, the following parameters were determined: form factor, elongation, roundness,

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32/37 sieve diameter, convexity and roughness. Depending on the value of these 6 parameters, the particles were divided into: pellets, agglomerates, with tails, multiple, long, dust, angel hair or badly cut.

[0077] The measurement of contaminants in pellets, together with the shape and size of the pellets, were performed using a PA66 consisting of a PS25C and a PSSD and or an equivalent instrument, configured by OCS GmbH. The PS25C and PSSD can be used independently and can be considered separate systems.

e) Flexural module [0078] The flexural module was determined in the 3-point curvature according to ISO 178 in test bars with 80 x 10 x 4 mm ³ , injection molded at 23 ° C in line with EN ISO 1873-2.

f) Vicat temperature [0079] Vicat temperature was measured according to ISO 306, method A50. A flat-tipped needle loaded with a 10 N mass is placed in direct contact with an injection molded test piece measuring 80 x 10 x 4 mm ³ , as described in EN ISO 1873-2. The specimen and the needle are heated to 50 ° C / h. The temperature at which the needle has been penetrated to a depth of 1 mm is recorded as the Vicat softening temperature.

g) Temperature of the gas stream

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33/37 [0080] The temperature of the gas stream was measured with thermocouples on two sides of the gas inlet on the gas distribution ring. In addition, the temperatures of the gas outlet and the upper part of the plastomer bed were measured as well.

h) Gas flow pressure [0081] The gas flow pressure was measured in the free headspace.

Experiments

Comparative example 1 (CE1) [0082] C2C8 raw granulated plastomer with 867 kg / m ³ density, 1.1 g / 10 minutes of MFR ₂ and 204 ppm initial VOC content (VOC, VDA277), as obtained by a solution polymerization process including pelletization, it was introduced into a silo with an internal diameter of 3.5 m. The total volume of the silo was approximately 165 m ³ . The gas used for aeration was air, which was introduced through a nozzle into a distribution ring placed below the bed of pellets. The pellets in the pellet bed were moved once in 24 hours, during the aeration process, to avoid the formation of lumps and plates.

[0083] During the aeration test, the upper level of the pellet bed was approximately 13 m from the distribution ring. The height / diameter ratio of the pellet bed was 3.75. The gas stream was set to 10.4 liters / (h-cm ² ) at a temperature of 25 ° C. The gas flow was

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14.7 m ³ / (ht). The total aeration time was 96 hours. After ο treatment, MFR2 and VOC content (VOC, VDA277) were determined: the granulated plastomer had the values of 1.1 g / 10 minutes and 79 ppm. The plastomeric MFR2 did not change during aeration and the VOC reduction rate was moderate. The formation of lumps and plates was not observed.

[0084] After aeration, the granulated plastomer was removed from the silo for measurement. The total gas flow in the 96-hour period was 1411 m ³ / ton, leading to a 204 ppm VOC reduction to 79 ppm, ie a reduction of approximately 61% or the need for approximately 11.3

m ³ / t flow in gas total for reduction of VOC's 1 ppm. Example 1 (Exl) [0085] Other lot plastomer C2C8 grainy in state

crude with a density of 867 kg / m ³ , 1.1 g / 10 minutes, as used in the comparative example, was subjected to the aeration process according to the invention. The initial VOC content (VOC, VDA277) of the raw granulated C2C8 plastomer, as obtained by a solution polymerization process including pelletization, ended up being 258 ppm. The raw granulated C2C8 plastomer was refilled in a 3.5 m inner diameter silo. The total volume of the silo was approximately 165 m ³ . The gas used for aeration was air, which was introduced through two nozzles in a distribution ring placed in the lower cone. The pellets in the pellet bed were moved twice (once in 24 hours) during the aeration process.

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35/37 [0086] During the aeration test, the upper level of the bed of the pellet bed was approximately 4 m from the distribution ring. The bed height / diameter ratio was 1.15. The gas stream was established at 31.2 liters / (h-cm ² ) with the temperature maintained between 28 and 30 ° C. The gas flow was 115.4 m ³ / (ht). The VOC content was monitored via sampling. The MFR2 of the plastomers again has not changed. In addition, the formation of lumps and plates was not observed.

[0087] After 21.5 hours, 42.2 hours and 45.2 hours, the granulated plastomer was removed from the silo and the measured VOC levels were 62 ppm, 9 ppm and 8 ppm, respectively. These values are given as the average of three samples from the bottom part, middle part and top part of the silo. After 21.5 hours, homogeneity was not completely achieved, as the VOC content was 28 ppm in the bottom, 76 ppm in the middle and 81 ppm in the top. After an aeration time of 45.2 hours, homogeneity was good at the bottom with VOC of 6 ppm, at the middle with 9 ppm and at the top with 8 ppm.

[0088] The total gas flow in the 45.2 hour period was 5216, 08 m ³ / t, leading to a VOC reduction of 258 ppm to 8 ppm, that is, a reduction of approximately 97%, or the need for approximately 20.9 m ³ / t of total gas flow for VOC reduction of 1 ppm.

Example 2 (Ex2) [008 9] Example 1 was repeated with the exception that the pellets in the pellet bed were not moved during the

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36/37 aeration process. A 2.7 times greater amount of another batch of the same granulated plastomer was used (plastomer C2C8 with 867 kg / m ³ density, 1.1 g / 10 minutes of MFR2). The initial VOC content was 202 ppm (VOC, VDA277). During the aeration test, the bed level was approximately 10.8 m from the distribution ring. The reading / bed diameter ratio was 3.08. The gas stream was again established at 31.2 liters / (h-cm ² ) with the temperature maintained between 28 and 30 ° C. The gas flow was 42.9 m ³ / (ht). After an aeration time of 78 hours, aeration was stopped. The VOC content was 2.2 ppm and MFR2 did not change, being, again, 1.1 g / 10 minutes. No formation of lumps and plates was observed.

[0090] The total gas flow in the period of 78 hours was 3346.2 m ³ / t, leading to a reduction of VOC 202 ppm to 2 ppm, that is, a reduction of approximately 99%, or the need for approximately 16 , 7 m ³ / t of total gas flow for a VOC reduction of 1 ppm. In addition to the VOC and MFR2 content, the amount of fine particles and the shape of the pellets during aeration were evaluated. Other properties of plastomers were not influenced by the aeration process. There was no exit block in any of the aeration tests.

Table 2

Value unity CE1 Exl Ex2 Before aeration mfr ₂ g / 10 min 1, 1 1, 1 1, 1 VOC ppm 204 258 202

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Density kg / m ³ 867 867 867 Aeration conditions Bed height / diameter ratio 3.75 1, 15 3, 08 Distance between the distribution ring and the bed m 13 4 10.8 Gaseous stream 1 / (h · cm ² ) 10, 4 31.2 31.2 Gas flow m ³ / (ht) 14, 7 115.4 42, 9 Gas temperature ° C 25 28 - 30 28 - 30 Moving pellets in bed Yes Yes No After aeration mfr ₂ g / 10 min 1, 1 1, 1 1, 1 VOC ppm 79 8 2.2 VOC reduction % 62 97 98, 9 t H 96 45.2 78 Lumps and / or plates No No No

Preparation of plastomers according to the present invention [0091] The preparation of plastomers of the present invention is described in EP 3 023 450, incorporated herein by reference in this patent application.

Claims (12)

1. Process for reducing the content of volatile organic compounds in granulated plastomers having: - density equal to or less than 883 kg / m ^3, and - MFR2 equal to or less than 100.0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C); below 65 ppm (VOC, VDA277), characterized by the process comprising the steps of: a) supply a raw granulated plastomer in a treatment container, the raw granulated plastomer having: - density equal to or less than 883 kg / m ³ ; - MFR2 equal to or less than 100.0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C); and content of volatile organic compounds (VOC, VDA277) above 150 ppm, B ) submits have said granulated plastomer in state gross a a stream of gas at range between 30 m ³ / (ht) and 150 m ³ / (h · t) for one time in aeration less than 96 hours, having the gas: - a minimum temperature of at least 26 ° C, measured at a gas inlet of the treatment vessel, and Petition 870190044306, of 05/10/2019, p. 49/56 2/5 a maximum temperature of 4 ° C below the Vicat temperature (10 N, ISO 306) of the raw granulated plastomer or 35 ° C measured at the gas inlet of the treatment vessel, whichever is the lower; and c) recover the granulated plastomer. Process according to claim 1, characterized in that the plastomers are copolymers of ethylene and octene, the plastomers being preferably produced by a solution polymerization process. Process according to any one of claims 1 and 2, characterized in that the process is carried out in batch. 4. Process for the production of granulated plastomer having: content of volatile organic compounds (VOC, VDA277) below 65 ppm; - density equal to or less than 883 kg / m ³ ; and - MFR2 equal to or less than 100.0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C), characterized by the process comprising the steps of: a) polymerize ethylene and 1-octene by solution polymerization in at least one polymerization reactor to produce a crude polymerization mixture, Petition 870190044306, of 05/10/2019, p. 50/56 3/5 b) recovering said crude polymerization mixture from at least one polymerization reactor and feeding said crude polymerization mixture to at least one flash vessel, thereby removing, at least partially, the solvent, unreacted monomer and unreacted comonomer for produce a raw plastomer, c) subjecting the raw plastomer to mixing and granulation, d) recover the granulated plastomer in the raw state having: - density equal to or less than 883 kg / m ³ ; and - MFR2 equal to or less than 100.0 g / 10 minutes (ISO 1133 with 2.16 kg load and 190 ° C); and content of volatile organic compounds (VOC, VDA277) above 150 ppm, e) subjecting said granulated plastomer in a raw state in a treatment vessel to a gas flow in the range between 30 m ³ / (ht) and 150 m ³ / (ht) for an aeration time of less than 96 hours, having the gas: a minimum temperature of at least 26 ° C, measured at a gas inlet of the treatment vessel, and - a maximum temperature of 4 ° C below the Vicat temperature (10 N, ISO 306) of the granulated plastomer or 35 ° C measured at the gas inlet Petition 870190044306, of 05/10/2019, p. 51/56 4/5 of the treatment container, whichever is lower, and f) recover the granulated plastomer. Process according to claim 4, characterized in that step e) is carried out in batch. 6. Process according to any of the claims of 1 to 5 characterized by the gas flow being in the range between 20.0 liters / (Irem ² ) and 35.0 liters / (h · cm ² ). 7. Process according to any one of claims 1 to 6, characterized in that the raw granulated plastomer is supplied in a treatment container and that the gas is injected from the bottom of the treatment container. 8. Process in a deal with any an of claims 1 to 7 featured by gas to be air. 9. Process 1 treatment claims to be an isolate. according to any of the to 8 characterized by the container of silo, preferably a silo 10. Process in a deal with any an of claims 1 to 9 characterized in that the raw granulated plastomer is not mixed or moved throughout the aeration time. Process according to any one of claims 1 to 10, characterized in that it comprises Petition 870190044306, of 05/10/2019, p. 52/56 5/5 still the step of subjecting the gas downstream of the treatment vessel to means for removing hydrocarbons. Process according to any one of claims 1 to 11, characterized in that the exhaust gas is discharged into the atmosphere. Process according to any one of claims 1 to 12, characterized in that the raw granulated plastomer has been preheated externally before the aeration time has started. Process according to any one of claims 1 to 13, characterized in that the granulated plastomer has a density of 870 kg / m ³ or less. 15. Granulated plastomer characterized by being able to be obtained by the process as defined in any one of claims 1 to 14.